<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Apr 16, 2012, at 3:30 PM, Chandler Carruth <<a href="mailto:chandlerc@google.com">chandlerc@google.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="font-family: Optima; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; ">Does sinking these into the DAGCombine layer help? How much does it break?</div></blockquote></div><br><div>I tried disabling just the InstCombine transforms that hide shl instructions behind bitmasks. Even though DAGCombine has the same transforms, it causes some pretty bad regressions:</div><div><br></div><div><div><font face="Menlo"><span style="font-size: 13px;">External/SPEC/CINT95/147_vortex/147_vortex 0.294 0.322 +9.6% +40mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">MultiSource/Benchmarks/Olden/tsp/tsp 0.680 0.748 +9.9% +41mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">SingleSource/Benchmarks/Shootout-C++/except 0.116 0.128 +10.8% +45mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">SingleSource/Benchmarks/Shootout/strcat 0.102 0.113 +11.1% +46mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">SingleSource/Benchmarks/Shootout-C++/hash 0.455 0.507 +11.4% +47mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">External/Povray/povray 2.015 2.246 +11.5% +47mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">External/SPEC/CINT2000/255_vortex/255_vortex 1.814 2.044 +12.7% +52mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">SingleSource/Benchmarks/Shootout-C++/heapsort 1.871 2.132 +13.9% +57mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">SingleSource/Benchmarks/Shootout-C++/ary3 1.087 1.264 +16.3% +65mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">MultiSource/Benchmarks/SciMark2-C/scimark2 27.491 23.596 -14.2% -66mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">MultiSource/Benchmarks/Olden/bisort/bisort 0.360 0.428 +19.0% +75mB</span></font></div><div><font face="Menlo"><span style="font-size: 13px;">MultiSource/Benchmarks/Olden/bh/bh 1.074 1.287 +19.9% +79mB</span></font></div></div><div><br></div><div>(Running on Sandy Bridge, x86-64)</div><div><br></div><div>I'll try to figure out why.</div><div><br></div><div>/jakob</div><div><br></div></body></html>